A device is known, which assists parallel parking by setting a route for the parallel parking of a vehicle. In such a parking assistance device, a technology is known, in which, for example, in a case where it is not possible to park the vehicle using the calculated route, the route is recalculated and set again.
JP 2009-83806A is an example of the related art.
However, in the technology in the related art, there is no disclosure regarding the recalculation of an available route for parking after one calculation, and there is a problem in that unnecessary recalculation of the route for the parallel parking which requires a large amount of calculation processing is executed.